github.com/jeffallen/go-ethereum@v1.1.4-0.20150910155051-571d3236c49c/core/chain_makers_test.go (about)

     1  // Copyright 2015 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package core
    18  
    19  import (
    20  	"fmt"
    21  	"math/big"
    22  
    23  	"github.com/ethereum/go-ethereum/core/types"
    24  	"github.com/ethereum/go-ethereum/crypto"
    25  	"github.com/ethereum/go-ethereum/ethdb"
    26  	"github.com/ethereum/go-ethereum/event"
    27  	"github.com/ethereum/go-ethereum/params"
    28  )
    29  
    30  func ExampleGenerateChain() {
    31  	params.MinGasLimit = big.NewInt(125000)      // Minimum the gas limit may ever be.
    32  	params.GenesisGasLimit = big.NewInt(3141592) // Gas limit of the Genesis block.
    33  
    34  	var (
    35  		key1, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
    36  		key2, _ = crypto.HexToECDSA("8a1f9a8f95be41cd7ccb6168179afb4504aefe388d1e14474d32c45c72ce7b7a")
    37  		key3, _ = crypto.HexToECDSA("49a7b37aa6f6645917e7b807e9d1c00d4fa71f18343b0d4122a4d2df64dd6fee")
    38  		addr1   = crypto.PubkeyToAddress(key1.PublicKey)
    39  		addr2   = crypto.PubkeyToAddress(key2.PublicKey)
    40  		addr3   = crypto.PubkeyToAddress(key3.PublicKey)
    41  		db, _   = ethdb.NewMemDatabase()
    42  	)
    43  
    44  	// Ensure that key1 has some funds in the genesis block.
    45  	genesis := WriteGenesisBlockForTesting(db, addr1, big.NewInt(1000000))
    46  
    47  	// This call generates a chain of 5 blocks. The function runs for
    48  	// each block and adds different features to gen based on the
    49  	// block index.
    50  	chain := GenerateChain(genesis, db, 5, func(i int, gen *BlockGen) {
    51  		switch i {
    52  		case 0:
    53  			// In block 1, addr1 sends addr2 some ether.
    54  			tx, _ := types.NewTransaction(gen.TxNonce(addr1), addr2, big.NewInt(10000), params.TxGas, nil, nil).SignECDSA(key1)
    55  			gen.AddTx(tx)
    56  		case 1:
    57  			// In block 2, addr1 sends some more ether to addr2.
    58  			// addr2 passes it on to addr3.
    59  			tx1, _ := types.NewTransaction(gen.TxNonce(addr1), addr2, big.NewInt(1000), params.TxGas, nil, nil).SignECDSA(key1)
    60  			tx2, _ := types.NewTransaction(gen.TxNonce(addr2), addr3, big.NewInt(1000), params.TxGas, nil, nil).SignECDSA(key2)
    61  			gen.AddTx(tx1)
    62  			gen.AddTx(tx2)
    63  		case 2:
    64  			// Block 3 is empty but was mined by addr3.
    65  			gen.SetCoinbase(addr3)
    66  			gen.SetExtra([]byte("yeehaw"))
    67  		case 3:
    68  			// Block 4 includes blocks 2 and 3 as uncle headers (with modified extra data).
    69  			b2 := gen.PrevBlock(1).Header()
    70  			b2.Extra = []byte("foo")
    71  			gen.AddUncle(b2)
    72  			b3 := gen.PrevBlock(2).Header()
    73  			b3.Extra = []byte("foo")
    74  			gen.AddUncle(b3)
    75  		}
    76  	})
    77  
    78  	// Import the chain. This runs all block validation rules.
    79  	evmux := &event.TypeMux{}
    80  	chainman, _ := NewChainManager(db, FakePow{}, evmux)
    81  	chainman.SetProcessor(NewBlockProcessor(db, FakePow{}, chainman, evmux))
    82  	if i, err := chainman.InsertChain(chain); err != nil {
    83  		fmt.Printf("insert error (block %d): %v\n", i, err)
    84  		return
    85  	}
    86  
    87  	state := chainman.State()
    88  	fmt.Printf("last block: #%d\n", chainman.CurrentBlock().Number())
    89  	fmt.Println("balance of addr1:", state.GetBalance(addr1))
    90  	fmt.Println("balance of addr2:", state.GetBalance(addr2))
    91  	fmt.Println("balance of addr3:", state.GetBalance(addr3))
    92  	// Output:
    93  	// last block: #5
    94  	// balance of addr1: 989000
    95  	// balance of addr2: 10000
    96  	// balance of addr3: 19687500000000001000
    97  }